Organic fluids of the borate-glycol type

ABSTRACT

CONDENSATION PRODUCTS PRODUCED BY REACTION OF AN ALKALI METAL ON ALKALINE EARTH METAL BORATE WITH A GLYCOL HAVING AT LEAST SEVEN CARBON ATOMS OR MIXTURES OF SUCH GLYCOLS WITH POLYHYDRIC ALCOHOLS HAVING 3 TO ABOUT 8 CARBON ATOMS. USEFUL AS CORROSION-INHIBITING ADDITIVES FO HYDRAULIC OR HEAT-EXCHANGING FLUIDS SUCH AS BRAKE FLUIDS.

United States Patent once 3,738,941 ORGANIC FLUIDS OTIf'YTIE BORATE-GLYCOL P John Frederick Collins, East Grinstead, England, assignor to United States Borax & Chemical Corporation, Los Angeles, Calif.

N Drawing. Filed Mar. 3, 1971, Ser. No. 120,723 Claims priority, application Great Britain, Mar. 10, 1970, 11,340/ 70 Int. Cl. C23 11/10, 11/18 US. Cl. 252-389 6 Claims ABSTRACT OF THE DISCLOSURE Condensation products produced by reaction of an al- Patented June 12, 1973 The glycols which can be used have seven or more carbon atoms, such as up to about 30 carbon atoms. Typical examples are tetraethylene glycol and the liquid polyethylene and polypropylene glycols of the formula where n is in the range of from about 4 to about 15. The molecular weights of such polyethylene and polypropylene glycols can range from about 200 to about 600.

The polyhydric alcohols contain from three to about eight carbon atoms. Examples of such alcohols include glycerol, trimethylolpropane, trimethylolethane, 1,2,4-butanetriol and 1,2,6-hexanetriol.

In the practice of this invention, the borate is dissolved in the appropriate glycol and polyhydric alcohol at a kali metal on alkaline earth metal bo With a glycOl concentration which will yield a product of convenient having at least seven carbon atoms or mixtures of such viscosity g y with polyhydric alcohols having 3 to about 8 Water is formed in the course of the condensation recarbon atoms. Useful as corrosion-inhibiting additives action and can b removed by vacuum ill i at a for hydraulic 0F heat-exchanging fluids Such as ake temperature up to the boiling point of the glycols used. fluids. The depression of boiling-point caused by adding compounds made according to this invention to hydraulic This invention relates to the preparation of novel confluids may b determined by any on i nt h d h densation products derived from alkali metal or alkalin; as SAEJ 1703 earth metal borates and certain glycols or mixtures o such glycols and polyhydric alcohols. The invention also EXAMPLES relates to the use of such condensation products as cor- The following reactions were carried out in a rotary rosion-inhibiting additives to h'ydraulic or heat-exchangevaporator. The b r e, g y and polyhydric alcohols ing fluids such as brake fluids, and to fluids containing were combined and heated to a maximum temperature of such additives. about 160 C. The water was distilled 01f under a vacuum It is known to use glycol-borate condensation products provided by a water pump (-10 mm. Hg). The boron for the above purposes. However, the conventional prodcontent of the product was analyzed. Boiling points of ucts of this type which are produced from glycols con- Castrol 525B hydraulic fluid containing 1% by weight of taining from two to six carbon atoms, bring about a subthe condensate was determined by SAEJ 1703a procestantial increase in the vapor-pressure and hence a dedure. Since the boiling point of the fluid without additives pression of the boiling-point of the hydraulic fluids convaried, results are reported as the drop in boiling point cerned. Recent developments in the production of hycaused by the additive.

Condensation product data Boron Weight of Depression Alkali metal i i iil i rem v d d h didiilic Example borate (amount) Glycol 0r gly l/P 13 01 mixture (amount) (percent) (g.) fluid F.) 3133::I:::5%]???.?ff:.:::::::: iyfiiifiiitiiiiitiiififi 5538i 8%? 5383 E3 31:: i i 0 dn Glycerol/tetraethylene glycol (1:3) (200 g. 2 8 10 D K2B407-LHZ g.) lycerol/polyethylene glycol* (1:1) (200 g.) 3 17 4 E Na2B-lO1-10H2O (38 g.) lycerolltetraethylene glycol (1:1) (200 g.) 2 10 3 *Molecular weight 200.

draulic fluids with very high boiling-points have rendered the use of conventional glycol-borate condensation products unsatisfactory.

Thus, the main object of the present invention is to provide an improved additive for hydraulic or heat-exchanging fluids which avoids excessive elevation of vaporpressure or depression of boiling-points of the fluids, as well as imparting corrosion-inhibiting properties thereto. An acceptable depression of boiling point, suggested by manufacturers of hydraulic fluids, is a maximum of about 10 F. for an addition of 1% by weight of the condensation product.

This may be achieved according to the present invention by use of condensation products formed between glycols having seven or more carbon atoms, or mixtures of said glycols and polyhydric alcohols having from three to about eight carbon atoms, and the borates of the alkali or alkaline earth metals. The borates are preferably the tetraborates, such as Na B O- .10H O, Na B 0 .5H O, K B 0 .4H O, CaB O .2H O, and the like. However, other other inorganic borates such as the metaborates and pentaborates of the alkali and alkaline earth metals may also be used if desired.

Various changes and modifications of the invention can 'be made and, to the extent that such variations incorporate the spirit of this invention, they are intended to be included within the scope of the appended claims.

What is claimed is:

1. Condensation product formed by dehydration of a mixture of alkali or alkaline earth metal borate with a polyethylene glycol or polypropylene glycol having at least seven carbon atoms and a molecular weight of from about 200 to about 600 and a polyhydric alcohol having three to about eight carbon atoms, the ratio of said glycol to said polyhydric alcohol being about 1:3 to about 3:1.

2. A condensation product in accordance with claim 1 in which said glycol has 7 to 30 carbon atoms.

3. A condensation product in accordance with claim 1 in which the borate is sodium tetraborate.

4. A condensation product in accordance with claim 1 in which the borate is potassium tetraborate.

5. A condensation product in accordance with claim 1 in which glycerol is mixed with said glycol.

6. A condensation product of potassium tetraborate, 3,325,423 6/1967 Jordan 252-78 glycerol and tetraethylene glycol in accordance with 2,979,524 4/1961 Wright 252-75 claim 1.

MAYER WEINBLA'IT, Primary Examiner References Clted 5 I. GLUCK, Assistant Examiner UNITED STATES PATENTS 3,403,104 9/1968 Sullivan 252-78 3,262,961 7/1966 Jordan 252-75 252-75, 78; 260-6065 B; 423-277 2,982,733 5/1961 Wright et a1. 252-75 

